Share This

A female wild-type axolotl (Ambystoma mexicanum). The most comprehensive study to date of the proteins in a species of salamander that can regrow appendages may provide important clues to how similar regeneration could be induced in humans.

Related Articles

Researchers at the School of Science at Indiana University-Purdue University Indianapolis and colleagues investigated over three hundred proteins in the amputated limbs of axolotls, a type of salamander that has the unique natural ability to regenerate appendages from any level of amputation, with the hope that this knowledge will contribute to a better understanding of the mechanisms that allow limbs to regenerate.

"In some ways this study of the axoltol's proteins was a fishing expedition. Fishing expedition can be a derogatory term in biology but for us it was positive, since we caught some important "fish" that enable us to formulate hypotheses as to how limb regeneration occurs," said David L. Stocum, Ph.D., professor of biology and director of the Indiana University Center for Regenerative Biology and Medicine, both in the School of Science at IUPUI, who led the study.

"Comparison of these proteins to those expressed in the amputated frog limb, which regenerates poorly, will hopefully allow us to determine how we might enhance limb regeneration in the frog and ultimately in humans, Dr. Stocum said.

With few exceptions -- notably the antlers of moose, deer and their close relatives, the tips of the fingers and toes of humans and rodents, and the ear tissue of certain strains of mice and rabbits -- the appendages of mammals do not regenerate after amputation.

Limb regeneration in the axolotl occurs when undifferentiated cells accumulate under the wound epidermis at the amputation site, a process known as the establishment of a blastema. These cells are derived by the reprogramming of differentiated cells to a less specialized state, and from resident stem cells.

"We found proteins that point to several areas that need to be studied closely to give us vital information about the mechanisms that operate to form a blastema that then goes on to regenerate the missing parts of the limb," said Dr. Stocum, an internationally respected cell and developmental biologist who has studied limb regeneration for over three decades.

Investigating the proteins found in the axolotl limb, the researchers noted three findings that appear to have significance in reprogramming cells to grow new limbs:

Quantities of enzymes involved in metabolism decreased significantly during the regeneration process.

There were many proteins that helped cells avoid cell death. Because amputation is very traumatic, this is critical.

A protein which appears to keep cells from dividing until they are fully dedifferentiated and reprogrammed to begin forming a new limb was expressed at high levels throughout blastema formation.

Findings were published online in the journal Biomedical Central Biology on November 30 (BMC Biology 7:83, 2009). Co-authors of the study, which was funded by the W. M. Keck Foundation, are Nandini Rao, Ph.D. and graduate student Behnaz Saranjami of the School of Science; graduate student Deepali Jhamb and Mathew Palakal, Ph.D. of the IU School of Informatics; Fengyu Song, D.D.S., M.S., Ph.D. of the IU School of Dentistry; Mu Wang, Ph.D. and Michael W. King, Ph.D. of the IU School of Medicine; Bingbing Li, Ph.D. of Central Michigan University; S. Randal Voss, Ph.D. of the University of Kentucky; and Derek J. Milner, Holly L. D. Nye and Jo Ann Cameron, Ph.D. of the University of Illinois. All except the final four are also affiliated with the IU Center for Regenerative Biology and Medicine.

The School of Science, IU Center for Regenerative Biology and Medicine, IU School of Dentistry, IU School of Informatics, and IU School of Medicine are all located on the IUPUI campus.

Indiana University School of Medicine. "How do salamanders grow a new leg? Protein mechanisms behind limb regeneration." ScienceDaily. ScienceDaily, 15 December 2009. <www.sciencedaily.com/releases/2009/12/091214121434.htm>.

Indiana University School of Medicine. (2009, December 15). How do salamanders grow a new leg? Protein mechanisms behind limb regeneration. ScienceDaily. Retrieved March 31, 2015 from www.sciencedaily.com/releases/2009/12/091214121434.htm

Indiana University School of Medicine. "How do salamanders grow a new leg? Protein mechanisms behind limb regeneration." ScienceDaily. www.sciencedaily.com/releases/2009/12/091214121434.htm (accessed March 31, 2015).

Featured Research

Mar. 31, 2015  As the five-year anniversary of the explosion of the Deepwater Horizon oil rig approaches, a new report looks at how twenty species of wildlife are faring in the aftermath of the ... full story

Mar. 31, 2015  Scientists have uncovered the earliest fossilized evidence of an insect caring for its young. The findings push back the earliest direct evidence of insect brood care by more than 50 million years, ... full story

Mar. 31, 2015  New research has scientists re-thinking how a lethal fungus grows and kills immune cells. The study hints at a new approach to therapy for Candida albicans, one of the most common causes of ... full story

Mar. 31, 2015  The most virulent strains of Streptococcus suis, the leading cause of bacterial meningitis in adult humans in parts of southeast Asia and in pigs around the world, are likely to have evolved and ... full story

Mar. 31, 2015  Darwin's evolutionary theory predicts survival of the fittest. So why do different survival tactics co-exist, if evolution should always favor the winning strategy? To answer that question scientists ... full story

Mar. 31, 2015  Scientists have discovered why the first buds of spring come increasingly earlier as the climate changes. As the climate changes the sweet spot for seeds comes earlier in the year, so first flowers ... full story

Mar. 31, 2015  Paleontologists have discovered two new species of Saurichthys. The ~242 million year old predatory fishes were found in the fossil Lagerstδtte Monte San Giorgio, in Ticino. They are distinct from ... full story

Mar. 31, 2015  In the 1990s the discovery of the oldest human made and completely preserved wooden hunting weapons made the Paleolithic excavation site in Schoningen internationally renowned. Contained within the ... full story

Mar. 31, 2015  The inherent ‘handedness’ of molecular structures directs the behavior of individual cells and confers them the ability to sense the difference between left and right. This is a significant step ... full story

Mar. 30, 2015  Scientists have found the genetic signature of enterovirus D68 in half of the California and Colorado children diagnosed with acute flaccid myelitis -- sudden, unexplained muscle weakness and ... full story

Featured Videos

Bionic Ants Could Be Tomorrow's Factory Workers

Reuters - Innovations Video Online (Mar. 30, 2015)  Industrious 3D printed bionic ants working together could toil in the factories of the future, says German technology company Festo. The robotic insects cooperate and coordinate their actions and movements to achieve a common aim. Amy Pollock reports.
Video provided by Reuters

Lions Make Surprise Comeback in Gabon

AFP (Mar. 30, 2015)  Lions have made a comeback in southeast Gabon, after disappearing for years, according to live footage from US wildlife organisation Panthera. Duration: 00:32
Video provided by AFP

Ancient Egyptian Beer Making Vessels Discovered in Israel

AFP (Mar. 30, 2015)  Fragments of pottery used by Egyptians to make beer and dating back 5,000 years have been discovered on a building site in Tel Aviv, the Israeli Antiquities Authority said on Sunday. Duration: 00:51
Video provided by AFP

Related Stories

June 19, 2014  The secret of how salamanders successfully regrow body parts is being unravelled by researchers in a bid to apply it to humans. For the first time, researchers have found that the 'ERK ... full story

Oct. 24, 2013  Cells triggering tissue regeneration that are taken from one limb and grafted onto another acquire the molecular "fingerprint," or identity, of their new location, developmental biologists ... full story

May 20, 2013  Salamanders' immune systems are key to their remarkable ability to regrow limbs, and could also underpin their ability to regenerate spinal cords, brain tissue and even parts of their hearts, ... full story

May 16, 2011  What does it take to regenerate a limb? Biologists have long thought that organ regeneration in animals like zebrafish and salamanders involved stem cells that can generate any tissue in the body. ... full story

ScienceDaily features breaking news and videos about the latest discoveries in health, technology, the environment, and more -- from major news services and leading universities, scientific journals, and research organizations.